TWENTY people were killed night when a passenger bus in Chad crashed into a truck that was broken down on the roadway, the government said. The bus had 31 people on board and was on its way from the capital N'Djamena to the eastern city of Abeche. It crashed near the town of Oum-Hadjer, the government said. "According to the first elements of the investigation, the causes identified are the non-respect of road safety rules... excessive speed, overloading, fatigue and carelessness of the driver," it said in a statement. It followed two bad accidents involving passenger buses this month in Senegal,…